Effects of phosphodiesterase-5 inhibitor sildenafil on esophageal secondary peristalsis: Studies with high-resolution manometry.

Abstract

Secondary peristalsis contributes to the clearance of retained refluxate from the esophagus. Sildenafil, a phosphodiesterase-5 inhibitor, inhibits primary esophageal peristalsis, but its effects on secondary peristalsis remain unknown. This study sought to investigate whether sildenafil could influence physiological characteristics of secondary peristalsis by applying high-resolution manometry (HRM). Seventeen healthy volunteers (15 men and 2 women, aged 30.2±6.4years) underwent two HRM studies on separate days following the administration of either a placebo or 50mg of sildenafil in a random order. Both studies were performed using a water-perfused HRM catheter containing one air injection channel positioned in the mid-esophagus. Secondary peristalsis was stimulated by a rapid mid-esophageal injection of 10 or 20mL of air 1h after the administration of either the placebo or sildenafil. The frequency and distal contractile integral of secondary peristalsis were then compared. Complete secondary peristalsis triggered by the 20-mL air injection was more frequent than observed with the 10-mL air injection (P<0.001). The vigor of secondary peristalsis triggered by the injection of either volume of air was lower than that of primary peristalsis (P<0.001). Sildenafil significantly reduced the success rate (P≤0.001) and vigor (P<0.001) of secondary peristalsis relative to the effects of the placebo at both distension volumes. Secondary peristalsis can be successfully triggered by rapid air injection during HRM. Sildenafil reduces both the success rate and the vigor of secondary peristalsis, similar to that seen with primary peristalsis.